Wich movie was it that i saw??

When i was about.. 7-10 years old maby older . I saw a movie were 2 austronauts landed on a planet and found a coffin with an alien inside. Sometning inside the coffin killed the austronaut. Some kind of fluid.

Yahoonas, I know the movie you're looking for, it's called Creature (1985) and it stars Klaus Kinski. At the very beginning of the movie, two astronauts discover an alien coffin. One of them sits on it so he can be photographed by the other, then suddenly the space beast awakens and kills the one sitting on the coffin.